CN113490825A

CN113490825A - Control method of refrigerator

Info

Publication number: CN113490825A
Application number: CN202080016890.9A
Authority: CN
Inventors: 尹皙俊; 林亨根; 李政勋; 李镐碝
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2019-02-28
Filing date: 2020-02-13
Publication date: 2021-10-08
Anticipated expiration: 2040-02-13
Also published as: KR102678956B1; CN113490825B; EP3933331A4; AU2020228522A1; KR20200105267A; EP3933331A1; AU2020228522B2; US20220146154A1; WO2020175826A1

Abstract

According to the control method of the refrigerator of the embodiment of the present invention, the freezing chamber load coping operation is performed if the heat load penetrates into the inside of the freezing chamber, and the internal temperature of the deep freezing chamber is differently set and controlled according to the open/close state of the deep freezing chamber mode, so that the freezing chamber load coping operation input condition can be differently set according to the open/close state of the deep freezing chamber mode.

Description

Control method of refrigerator

Technical Field

The invention relates to a control method of a refrigerator.

Background

In general, a refrigerator, which is a home appliance for storing food at a low temperature, includes a refrigerating chamber for storing food in a refrigerated state in a range of 3 ℃ and a freezing chamber for storing food in a frozen state in a range of-20 ℃.

However, if food such as meat or seafood is stored in a frozen state in the current freezing chamber, water in cells of the meat or seafood flows out of the cells to cause the cells to be damaged during freezing of the food to-20 ℃, and a phenomenon in which the taste is changed during thawing occurs.

However, if the temperature condition of the storage chamber is set to a very low temperature state significantly lower than the current freezing chamber temperature, whereby the food rapidly passes through the freezing point temperature range when changing to the frozen state, it is possible to minimize cell destruction, and as a result, there is an advantage that the meat quality and taste after thawing can be restored to a state close to the state before freezing. The very low temperature is understood to mean a temperature in the range from-45 ℃ to-50 ℃.

For this reason, in recent years, the demand for a refrigerator provided with a deep freezing chamber that maintains a temperature lower than that of the freezing chamber is gradually increasing.

In order to meet the demand for the deep freezing chamber, there is a limit in cooling using an existing refrigerant, and thus, an attempt is being made to lower the temperature of the deep freezing chamber to an extremely low temperature using a ThermoElectric Element (TEM).

In korean laid-open patent No. 10-2018-0105572 (09/28/2018) (prior art), a refrigerator in the form of a bedside cabinet using a thermoelectric module to store a storage room at a temperature lower than the indoor temperature is disclosed.

However, in the case of the refrigerator using the thermoelectric module disclosed in the above-described prior art 1, since the heat generating surface of the thermoelectric module has a structure in which the heat is exchanged with the indoor air and cooled, there is a limit to reduce the temperature of the heat absorbing surface.

In detail, with the thermoelectric module, if the supply current increases, the temperature difference between the heat absorbing surface and the heat generating surface tends to increase to a certain level. However, in consideration of the characteristics of the thermoelectric element made of a semiconductor element, if the supply current increases, the semiconductor functions as a resistance, resulting in an increase in self-heating value. Then, there is a problem that the heat absorbed from the heat absorbing surface cannot be quickly transferred to the heat generating surface.

Furthermore, if the heat generating surface of the thermoelectric element is not sufficiently cooled, the heat transferred to the heat generating surface flows back to the heat absorbing surface side, and the temperature of the heat absorbing surface is also increased.

In the case of the thermoelectric module disclosed in prior art 1, since the heat generating surface is cooled by the indoor air, there is a limit that the temperature of the heat generating surface cannot be made lower than the indoor temperature.

In a state where the temperature of the heat generating surface is substantially fixed, it is necessary to increase the supply current to lower the temperature of the heat absorbing surface, thereby causing a problem of lowering the efficiency of the thermoelectric module.

In addition, if the supply current is increased, the temperature difference between the heat absorbing surface and the heat generating surface becomes large, resulting in a decrease in the cooling capability of the thermoelectric module.

Therefore, in the case of the refrigerator disclosed in prior art 1, it is impossible to lower the temperature of the storage chamber to an extremely low temperature significantly lower than the temperature of the freezer chamber, so to speak only to the extent of maintaining the temperature level of the refrigerator chamber.

In order to overcome the limitations of such thermoelectric modules and to reduce the temperature of the storage chamber to a temperature lower than that of the freezing chamber using the thermoelectric modules, a great deal of experiments and studies have been conducted. As a result, in order to cool the heat generating surface of the thermoelectric module to a low temperature, it has been attempted to attach an evaporator, through which a refrigerant flows, to the heat generating surface.

Korean laid-open patent No. 10-2016-.

However, the prior art 2 also has problems.

In prior art 2, no description is given at all of the operation control method between the evaporator for cooling the heat generating surface of the thermoelectric module and the freezing compartment evaporator. In detail, since a so-called deep freezing chamber cooled by the thermoelectric module is accommodated in the freezing chamber, when a load is applied to either or both of the freezing chamber and the deep freezing chamber, there is no disclosure at all of a method of controlling a refrigerant cycle system for preferentially performing a load-handling operation of which storage chamber is to be operated.

In prior art 2, nothing is disclosed at all about how to perform the load handling operation when a load is applied to the refrigerating room other than the freezing room. This means that only the structure of a cooling device using an evaporator as a heat generating surface of a thermoelectric element has been studied, and problems that occur with an input load when actually applied to a refrigerator and a control method for eliminating the problems have not been studied.

For example, when a load is applied to the freezing chamber, moisture is generated inside the freezing chamber, and if the moisture is not removed quickly, the moisture adheres to the outer wall of the deep freezing chamber, and frost is formed.

In particular, when loads are applied to the refrigerating compartment and the freezing compartment at the same time, the refrigerating compartment load coping operation is preferentially performed, and the freezing compartment load coping operation is not performed. That is, even if a load is applied to the freezing chamber during the operation of the refrigerating chamber for coping with load, the freezing chamber fan is not driven, and therefore, there is a problem that the moisture generated in the freezing chamber cannot be prevented from adhering to the outer wall of the deep freezing chamber and growing.

Furthermore, in the case where the indoor space where the refrigerating chamber is provided is in a low temperature region such as in winter, since the operation rate of the freezing chamber fan is low, moisture generated inside the freezing chamber cannot be rapidly removed, thereby possibly causing a problem that frost is generated on the outer wall of the deep freezing chamber.

A more serious problem is that if frost is generated on the outer wall of the deep freezing chamber, the user can directly physically defrost the frost, or the user can wait until the freezing chamber temperature rises to a temperature at which frost can be melted by stopping the operation of the freezing chamber, but there is no other suitable method.

If a user removes frost attached to the outer wall of the deep freezing chamber using a tool (tool), there is a problem in that the outer wall of the deep freezing chamber may be damaged.

If a method of melting frost by stopping the operation of the freezing chamber is selected, the following problems may be caused: the food stored in the freezing chamber is deteriorated as soon as the food is not moved elsewhere.

Although the refrigerator having the structure in which the deep freezing chamber is accommodated inside the freezing chamber has serious problems as described above, in the related art 2, there is no mention of these conceivable problems nor a coping method for the problems that occur.

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above-mentioned problems.

In particular, an object of the present invention is to provide a control method for rapidly reducing the temperature of each storage chamber to a temperature range satisfying the temperature range when a load is applied to the refrigerating chamber and the freezing chamber depending on whether the deep freezing chamber mode is in an open state or in a closed state.

Specifically, an object of the present invention is to provide a control method of a refrigerator capable of preventing a problem of frost generation on an outer wall of a deep freezing chamber when a load is applied to an inside of a freezing chamber.

In addition, since the probability of frost formation on the outer wall of the deep freezing chamber becomes different according to the indoor temperature, it is an object of the present invention to design a control method for preventing frost formation differently according to the indoor temperature, thereby being capable of preventing the problem of frost formation regardless of the indoor temperature.

Technical scheme for solving problems

In the control method of the refrigerator according to the embodiment of the present invention for achieving the above-described object, since the freezing chamber load coping operation is performed when the heat load penetrates into the inside of the freezing chamber, and the internal temperature of the deep freezing chamber is differently set and controlled according to the open/close state of the deep freezing chamber mode, the freezing chamber load coping operation input conditions may be differently set according to the open/close state of the deep freezing chamber mode.

Specifically, the first freezing compartment load coping operation input condition is applied when the deep freezing compartment mode is in the open state, the second freezing compartment load coping operation input condition is applied when the deep freezing compartment mode is in the closed state, and the minimum value of the heat load satisfying the first freezing compartment load coping operation input condition may be set to be smaller than the minimum value of the heat load satisfying the second freezing compartment load coping operation input condition.

In addition, if the freezing chamber load coping operation input condition is satisfied, it is determined whether an indoor temperature condition is satisfied, and the indoor temperature condition may be differently applied according to an on/off state of the deep freezing chamber mode.

Here, an indoor temperature range (RT Zone) in which a load-handling operation of the freezing chamber can be performed when the deep freezing chamber mode is in the on state may be defined as a first indoor temperature range; an indoor temperature range (RT Zone) in which the load of the freezing chamber can be put into the operation in response to the load of the freezing chamber when the deep freezing chamber mode is in the off state may be defined as a second indoor temperature range.

The first indoor temperature region may be set to be wider than the second indoor temperature region.

The lowest indoor temperature belonging to the first indoor temperature region may be set to be lower than the lowest indoor temperature belonging to the second indoor temperature region.

If it is determined that the indoor temperature Zone (RT Zone) to which the current indoor temperature belongs is an indoor temperature Zone in which the load-handling operation for the freezing compartment can be put into operation, the control unit may determine whether or not there is a conflict between the load-handling operation for the refrigerating compartment and the load-handling operation for the freezing compartment.

If it is determined that the refrigerating room load coping operation and the freezing room load coping operation conflict with each other, the refrigerating room load coping operation is stopped, and the refrigerating room load coping operation is executed first, so that the storage room satisfying a high temperature is cooled first.

If the refrigerating room load handling operation is performed in priority to the freezing room load handling operation, the freezing room fan may be controlled to be driven at a low speed.

When the temperature of the refrigerating chamber enters the temperature-satisfying range, the load-supporting operation for the freezing chamber is released and the driving of the freezing chamber fan is stopped at the same time as the load-supporting operation for the refrigerating chamber is completed.

The method may further include the step of determining whether or not the first freezer compartment load coping operation input condition is satisfied when the freezer compartment load coping operation is released in an open state of the deep freezer compartment mode, and the step of determining whether or not the second freezer compartment load coping operation input condition is satisfied when the freezer compartment load coping operation is released in a closed state of the deep freezer compartment mode.

When the deep freezing chamber mode is in the on state and the temperature of the refrigerating chamber enters the temperature satisfying region, the refrigerating chamber load coping operation may be ended, and the control part may newly determine whether the first refrigerating chamber load coping operation input condition is satisfied while the freezing chamber fan is kept driven at a low speed.

Alternatively, if the deep freezer mode is in the on state and the freezer compartment temperature enters the temperature satisfying region, the freezer compartment load handling operation may be terminated and the freezer compartment load handling operation may be continuously performed.

If it is determined that the refrigerating room load coping operation input condition is not satisfied, the freezing room load coping operation may be executed, and if the freezing room temperature enters the satisfied temperature region or a set time has elapsed after the execution of the freezing room load coping operation is started, the freezing room load coping operation may be canceled.

In addition, when the temperature of the refrigerating chamber enters the upper limit region while the load coping operation of the freezing chamber is being performed, it is possible to switch to the simultaneous operation mode in which the refrigerating chamber and the freezing chamber are cooled simultaneously.

In addition, when at least one of the refrigerating chamber temperature and the freezing chamber temperature enters a temperature-satisfying range while the simultaneous operation mode is being executed, the freezing chamber load handling operation can be cancelled.

Effects of the invention

According to the control method of the refrigerator of the embodiment of the present invention having the above-described configuration, the following effects are provided.

First, according to the control method of the present invention, if it is detected that a load is put into the interior of the freezing chamber in which the deep freezing chamber is accommodated, the freezing chamber load coping operation is immediately performed, so that moisture generated in the interior of the freezing chamber is discharged to the freezing-evaporating chamber in which the freezing chamber evaporator is accommodated.

In this way, the moisture sent to the inside of the freezing-evaporation chamber can be attached to the surface of the freezing-chamber evaporator, and condensed into water by the defrosting operation of the freezing-chamber evaporator and discharged to the outside of the refrigerator.

Therefore, the following advantages are provided: the user does not need to remove the frost formed on the outer wall of the deep freezing chamber by a tool or a hand, and does not need to raise the temperature of the freezing chamber to the freezing temperature or more for defrosting.

Furthermore, when the load of the refrigerating compartment and the load of the freezing compartment are increased simultaneously or at intervals, that is, when the load-handling operation conflicts with each other, there are the following advantages: the load coping operation is appropriately controlled in the priority order, so that it is possible to minimize the phenomenon that frost is generated on the outer wall of the deep freezing chamber or the inner wall of the freezing chamber.

In addition, the following advantages are provided: in consideration of the characteristic that the deep freezing chamber is sensitive to the indoor temperature, the load coping operation is appropriately performed according to the type of the indoor temperature, so that the phenomenon of frost generation on the outer wall of the deep freezing chamber or the inner wall of the freezing chamber can be minimized.

Drawings

Fig. 1 is a diagram showing a refrigerant cycle system of a refrigerator to which a control method of an embodiment of the present invention is applied.

Fig. 2 is a perspective view illustrating the structures of a freezing chamber and a deep freezing chamber of a refrigerator according to an embodiment of the present invention.

Fig. 3 is a longitudinal sectional view taken along line 3-3 of fig. 2.

Fig. 4 is a graph showing cooling capacity versus input voltage and fourier effect.

Fig. 5 is a graph showing the efficiency relationship with respect to the input voltage and the fourier effect.

Fig. 6 is a graph showing the correlation of the cooling capacity and the efficiency based on the voltage.

Fig. 7 is a graph illustrating a reference temperature line for controlling the refrigerator according to a load variation inside the refrigerator.

Fig. 8 and 9 are flowcharts illustrating a control method of the freezing chamber load coping operation according to the embodiment of the present invention.

Fig. 10 is a flowchart illustrating a control method for controlling the output of the freezing chamber fan in the on state of the deep freezing chamber mode.

Fig. 11 is a flowchart illustrating a control method for controlling the output of the freezing chamber fan in the closed state of the deep freezing chamber mode.

Detailed Description

Hereinafter, a control method of a refrigerator according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, a storage chamber that is cooled by a first cooling device and can be controlled to a prescribed temperature may be defined as the first storage chamber.

In addition, a storage chamber that is cooled by the second cooler and can be controlled to a temperature lower than that of the first storage chamber may be defined as the second storage chamber.

In addition, a storage chamber that is cooled by a third cooler and can be controlled to a temperature lower than that of the second storage chamber may be defined as a third storage chamber.

The first cooler for cooling the first storage chamber may include at least one of a first evaporator and a first thermoelectric module including a thermoelectric element. The first evaporator may include a refrigerating compartment evaporator described later.

The second cooler for cooling the second storage chamber may include at least one of a second evaporator and a second thermoelectric module including a thermoelectric element. The second evaporator may include a freezing chamber evaporator described later.

The third cooler for cooling the third storage chamber may include at least one of a third evaporator and a third thermoelectric module including a thermoelectric element.

In the present specification, for an embodiment in which a thermoelectric module is used as a cooling device, an evaporator can be applied instead of the thermoelectric module, and the following example is given.

(1) The "cold-side heat sink of the thermoelectric module" or the "heat absorbing surface of the thermoelectric element" or the "heat absorbing side of the thermoelectric module" may be interpreted as "evaporator or one side of the evaporator".

(2) The "heat absorption side of the thermoelectric module" may be interpreted as the same meaning as "cold-side heat sink of the thermoelectric module" or "heat absorption surface of the thermoelectric module".

(3) The control portion "apply or cut off the forward voltage to the thermoelectric module" may be interpreted as the same meaning as "supply or cut off the refrigerant to the evaporator", "control to switch the valve to be opened or closed", or "control to switch the compressor to be opened or closed".

(4) The control portion "controls to increase or decrease the forward voltage applied to the thermoelectric module" may be interpreted as the same meaning as "controlling the flow rate or flow rate of the refrigerant flowing to the evaporator to increase or decrease", "controlling to increase or decrease the opening degree of the switching valve", or "controlling to increase or decrease the output of the compressor".

(5) The control portion "controls to increase or decrease the reverse voltage applied to the thermoelectric module" may be interpreted as the same meaning as "controls to increase or decrease the voltage applied to the defrosting heater adjacent to the evaporator".

On the other hand, in the present specification, "a storage chamber cooled by a thermoelectric module" may be defined as a storage chamber a, and "a fan located at a position adjacent to the thermoelectric module and configured to exchange heat between air inside the storage chamber a and a heat absorbing surface of the thermoelectric module" may be defined as a storage chamber a fan.

In addition, a storage chamber which constitutes a refrigerator together with the storage chamber a and is cooled by a cooler may be defined as "storage chamber B".

In addition, the "cooler compartment" may be defined as a space where the cooler is located, and in a structure in which a fan for blowing cool air generated from the cooler is further provided, may be defined as including a space for accommodating the fan, and in a structure in which a flow path for guiding cool air blown from the fan to the storage chamber or a flow path for discharging defrost water is further provided, may be defined as including the flow path.

In addition, a defrosting heater provided at one side of the cold-side radiator in order to remove frost or ice formed at the cold-side radiator or the periphery thereof may be defined as a cold-side radiator defrosting heater.

In addition, a defrosting heater provided at one side of the hot-side radiator to remove frost or ice formed at the hot-side radiator or the periphery thereof may be defined as a hot-side radiator defrosting heater.

In addition, a defrosting heater provided at one side of the cooler in order to remove frost or ice formed at the cooler or the periphery thereof may be defined as a cooler defrosting heater.

In addition, a defrosting heater provided at one side of a wall surface for forming a cooler compartment in order to remove frost or ice formed on the wall surface for forming the cooler compartment or the periphery thereof may be defined as a cooler compartment defrosting heater.

The heater disposed on one side of the cold-side radiator to minimize re-icing or re-frosting during discharging melted defrosting water or water vapor from the cold-side radiator or the periphery thereof may be defined as a cold-side radiator drain (drain) heater.

The heater disposed on one side of the hot-side radiator to minimize re-icing or re-frosting in the process of discharging melted defrosting water or steam from the hot-side radiator or the periphery thereof may be defined as a hot-side radiator drain heater.

The heater disposed on one side of the cooler to minimize re-icing or re-frosting during the process of discharging the melted defrosting water or steam from the cooler or the periphery thereof may be defined as a cooler drain heater.

Further, a heater disposed on one side of the wall surface forming the cooler chamber in order to minimize re-icing or re-frosting in the process of discharging melted defrosting water or steam from the wall surface forming the cooler chamber or the periphery thereof may be defined as a cooler chamber drain heater.

In addition, a "cold-side radiator heater" to be described below may be defined as a heater that performs at least one of the functions of the cold-side radiator defrosting heater and the cold-side radiator draining heater.

In addition, a "hot-side radiator heater" may be defined as a heater that performs at least one of the functions of the hot-side radiator defrost heater and the hot-side radiator drain heater.

In addition, a "cooler heater" may be defined as a heater performing at least one of a function of the cooler defrost heater and a function of the cooler drain heater.

In addition, a back heater, which will be described below, may be defined as a heater that performs at least one of the functions of the hot-side radiator heater and the cooler chamber defrost heater. That is, the back heater may be defined as a heater that performs at least one of the functions of the hot-side radiator defrost heater, the hot-side radiator drain heater, and the cooler chamber defrost heater.

In the present invention, the first storage chamber may include a refrigerating chamber, and the refrigerating chamber may be controlled to a temperature above zero by the first cooler, as an example.

In addition, the second storage chamber may include a freezing chamber, and the freezing chamber may be controlled to a sub-zero temperature by the second cooler.

In addition, the third storage chamber may include a deep freezing chamber (deep freezing chamber) which may be maintained at a very low temperature (cryogenic temperature) or an ultra-low temperature (ultra-freezing temperature) by the third cooler.

In addition, the invention does not exclude: a case where the first to third storage chambers are all controlled to a subzero temperature; a case where the first to third storage chambers are all controlled to a temperature above zero; and a case where the first storage chamber and the second storage chamber are controlled to an above-zero temperature, and the third storage chamber is controlled to a below-zero temperature.

In the present invention, "operation" of the refrigerator may be defined to include four operation steps, which are: a step I for judging whether or not an operation start condition or an operation input condition is satisfied; step II of executing preset operation under the condition of meeting the operation input condition; step III of judging whether the operation completion condition is met; and a step IV of ending the operation when the operation completion condition is satisfied.

In the present invention, "operation" for cooling the storage chamber of the refrigerator may be defined by distinguishing general operation from special operation.

The general operation may refer to a cooling operation performed when the temperature inside the refrigerator naturally rises in a state where the opening of the storage compartment door or the load input condition caused by storing food does not occur.

In detail, it is defined that, when the temperature of the storage chamber enters a region that does not satisfy the temperature (hereinafter, described in detail with reference to the drawings) and the operation input condition is satisfied, the control part controls the supply of cold air from the cooler of the storage chamber in order to cool the storage chamber.

Specifically, the general operation may include a refrigerating compartment cooling operation, a freezing compartment cooling operation, a deep freezing compartment cooling operation, and the like.

On the contrary, the special operation may refer to an operation other than the operation defined as the general operation.

In detail, the special operation may include a defrosting operation controlled to supply heat to the cooler to melt frost or ice formed on the cooler while passing through a defrosting cycle of the storage chamber.

In addition, the special operation may further include a load handling operation controlled to supply cold air from the cooler to the storage chamber to remove a heat load penetrating into the storage chamber if an operation input condition is satisfied by satisfying at least one of the following conditions: a case where a set time has elapsed from a time point when a door of the storage chamber is closed after being opened; or the temperature of the storage chamber rises to the set temperature before the set time elapses.

In detail, the load handling operation may include: a door load coping operation performed to remove a load penetrating into the storage chamber after an opening/closing operation of the storage chamber door; and an initial cold start operation performed in order to remove a load inside the storage chamber when power is first applied after the refrigerator is installed.

For example, the defrosting operation may include at least one of a refrigerating chamber defrosting operation, a freezing chamber defrosting operation, and a deep freezing chamber defrosting operation.

In addition, the door load coping operation may include at least one of a refrigerating chamber door load coping operation, a freezing chamber door load coping operation, and a deep freezing chamber load coping operation.

Here, the deep freezing chamber load coping operation may be interpreted as referring to an operation for removing a deep freezing chamber load, and the deep freezing chamber load coping operation is performed if at least one of the following conditions is satisfied, the conditions including: a deep freezing chamber door load coping operation input condition executed when a load is increased with the opening of the deep freezing chamber door; initial cold start operation input conditions of the deep freezing chamber executed for removing the load in the deep freezing chamber when the deep freezing chamber is switched from a closed state to an open state; and a post-defrosting operation input condition which is started for the first time after the defrosting operation of the deep freezing chamber is completed.

In detail, the determining whether the load coping operation input condition of the deep freezing chamber door is satisfied may include determining whether at least one of the following conditions is satisfied, the conditions including: a condition that a predetermined time elapses from a time point at which at least one of the freezing chamber door and the deep freezing chamber door is closed after being opened; and the condition that the temperature of the deep freezing chamber rises to the set temperature within a predetermined time.

In addition, the case of determining whether the initial cold start operation input condition of the deep freezing chamber is satisfied may include a case of determining whether the power of the refrigerator is turned on and the deep freezing chamber mode is switched from the off state to the on state.

Further, the determining whether the operation input condition is satisfied after the deep freezing chamber is defrosted may include determining at least one of: the cold side radiator heater is turned off; the back heater is turned off; the reverse voltage applied to the thermoelectric module in order to perform defrosting of the cold-side radiator is interrupted; after applying the reverse voltage in order to perform the defrosting of the cold side radiator, the forward voltage applied to the thermoelectric module in order to perform the defrosting of the hot side radiator is interrupted; the temperature of the housing for accommodating the hot-side heat sink is raised to a set temperature; and the freezing chamber defrosting operation is ended.

Therefore, the operation of the storage compartment including at least one of the refrigerating compartment, the freezing compartment, and the deep freezing compartment may be arranged to include a storage compartment general operation and a storage compartment special operation.

On the other hand, in the case where two operations of the operation of the storage chamber conflict with each other as described above, the control unit may control to preferentially perform one of the operations (operation a) and to interrupt (pause) the other operation (operation B).

In the present invention, operational conflicts may include: i) a case where the input conditions of operation a and the input conditions of operation B are simultaneously satisfied and conflict occurs; ii) during the execution of the operation a while the input conditions of the operation a are satisfied, a conflict may occur due to the input conditions of the operation B being satisfied; and iii) when the input condition of the operation A is satisfied while the operation B is executed while the input condition of the operation B is satisfied, a collision occurs.

In the case where two operations collide, the control portion executes a so-called "collision control algorithm" to determine the execution priority of the operation in which the collision occurs, and controls the execution of the corresponding operation.

The case where the operation a is preferentially executed and the operation B is interrupted will be described as an example.

In detail, in the present invention, the interrupted operation B may be controlled so as to follow the procedure of at least any one of the three cases exemplified below after the operation a is completed.

a. Relieving operation B (termination)

When operation a is completed, execution of operation B may be canceled, thereby ending the collision control algorithm and returning to the previous operation step.

Here, "release" means that not only the operation B that has been interrupted is not executed any more, but also whether or not the input condition of the operation B is satisfied is not determined. That is, it can be considered that the determination information of the input condition for the operation B is initialized.

b. Redetermination of input conditions for operation B

When the operation a which is preferentially executed is completed, the control unit may return to the step of determining again whether the input condition of the operation B which has been interrupted is satisfied, and may determine whether to restart (restart) the operation B.

For example, if the operation B is an operation in which the fan is driven for 10 minutes, and if the operation is interrupted at the time point when 3 minutes have elapsed after the start of the operation due to a conflict with the operation a, it is determined again at the time point when the operation a is completed whether the input condition of the operation B is satisfied, and if it is determined that the input condition is satisfied, the fan is driven for 10 minutes again.

c. Continuation of operation B (continuation)

When the operation a that is preferentially executed is completed, the control unit may control to continue the operation B that is interrupted. Here, "continuation" means that the interrupted operation is continued, not executed again from the beginning.

For example, if operation B is an operation in which the fan is driven for 10 minutes, and the operation is interrupted at the time point when 3 minutes have elapsed after the start of the operation due to a conflict with operation a, the compressor is re-driven for a remaining time of 7 minutes immediately from the time point when operation a ends.

On the other hand, in the present invention, the priority of the operation may be determined as follows.

First, if the normal operation and the special operation conflict with each other, the special operation can be controlled to be preferentially executed.

Second, in the case where a conflict occurs with the general operation, the priority of the operation may be determined as follows.

I. If the refrigerating compartment cooling operation and the freezing compartment cooling operation conflict with each other, the refrigerating compartment cooling operation may be preferentially performed.

If the refrigerating chamber (or freezing chamber) cooling operation conflicts with the deep freezing chamber cooling operation, the refrigerating chamber (or freezing chamber) cooling operation may be preferentially performed. At this time, in order to prevent the deep freezing chamber temperature from excessively rising, a cooling capacity lower than the maximum cooling capacity level of the deep freezing chamber cooler may be supplied from the deep freezing chamber cooler to the deep freezing chamber.

The cooling capacity may refer to at least one of a cooling capacity of the cooler itself and a blowing amount of a cooling fan located at a position adjacent to the cooler. For example, in the case where the cooler of the deep freezing chamber is a thermoelectric module, if the refrigerating chamber (or freezing chamber) cooling operation conflicts with the deep freezing chamber cooling operation, the control unit may control to preferentially perform the refrigerating chamber (or freezing chamber) cooling operation and input a voltage lower than the maximum voltage applicable to the thermoelectric module.

Third, in the case where a conflict with a special operation occurs, the priority of the operation may be determined as follows.

I. The control unit may control the operation of the load handling operation of the refrigerating chamber door to be preferentially performed if the operation of the load handling operation of the refrigerating chamber door conflicts with the operation of the load handling operation of the freezing chamber door.

If the freezer door load coping operation conflicts with the deep freezer door load coping operation, the control part may control to preferentially perform the deep freezer door load coping operation.

The control part may control to simultaneously perform the refrigerating chamber operation and the deep freezing chamber door load coping operation if the refrigerating chamber operation conflicts with the deep freezing chamber door load coping operation, and then may control to separately perform the deep freezing chamber door load coping operation if the refrigerating chamber temperature reaches a specific temperature a. If the refrigerating compartment temperature rises again and reaches a certain temperature b (a < b) during the separate execution of the deep freezing compartment door load coping operation, the control part may control to simultaneously execute the refrigerating compartment operation and the deep freezing compartment door load coping operation again. Thereafter, the operation switching process between the simultaneous operation of the deep freezing chamber and the refrigerating chamber and the separate operation of the deep freezing chamber may be repeatedly performed according to the refrigerating chamber temperature control.

On the other hand, as an expanded modification, if the operation input condition of the deep freezer load coping operation is satisfied, the control unit may control to execute the same operation as the case where the refrigerating room operation conflicts with the deep freezer door load coping operation.

Hereinafter, as an example, a case where the first storage chamber is a refrigerating chamber, the second storage chamber is a freezing chamber, and the third storage chamber is a deep freezing chamber will be described.

Fig. 1 is a diagram illustrating a refrigerant cycle system of a refrigerator according to an embodiment of the present invention.

Referring to fig. 1, a refrigerant cycle system 10 of an embodiment of the present invention includes: a compressor 11 for compressing a refrigerant into a high-temperature high-pressure gas refrigerant; a condenser 12 for condensing the refrigerant discharged from the compressor 11 into a high-temperature and high-pressure liquid refrigerant; an expansion valve for expanding the refrigerant discharged from the condenser 12 into a low-temperature low-pressure two-phase refrigerant; and an evaporator for evaporating the refrigerant passing through the expansion valve into a low-temperature low-pressure gas refrigerant. The refrigerant discharged from the evaporator flows into the compressor 11. The above-described configuration is connected to each other by refrigerant pipes to form a closed circuit.

In detail, the expansion valves may include a refrigerating compartment expansion valve 14 and a freezing compartment expansion valve 15. The refrigerant pipe is divided into two branches at the outlet side of the condenser 12, and the refrigerating chamber expansion valve 14 and the freezing chamber expansion valve 15 are connected to the refrigerant pipe divided into two branches, respectively. That is, the refrigerating chamber expansion valve 14 and the freezing chamber expansion valve 15 are connected in parallel at the outlet side of the condenser 12.

A switching valve 13 is attached to the outlet side of the condenser 12 at a position where the refrigerant pipe is divided into two branches. By the adjustment operation of the opening degree of the switching valve 13, the refrigerant passing through the condenser 12 can be made to flow only to either one of the refrigerating chamber expansion valve 14 and the freezing chamber expansion valve 15, or can be branched to both sides.

The switching valve 13 may be a three-way valve, and determines a flow direction of the refrigerant according to an operation mode. Here, one switching valve, for example, the three-way valve may be attached to the outlet side of the condenser 12 to control the flow direction of the refrigerant, or alternatively, an opening/closing valve may be attached to each of the inlets of the refrigerating chamber expansion valve 14 and the freezing chamber expansion valve 15.

On the other hand, as a first example of the configuration of the evaporator, the evaporator may include: a refrigerating chamber evaporator 16 connected to an outlet side of the refrigerating chamber expansion valve 14; and a hot-side radiator 24 and a freezing chamber evaporator 17 connected in series to an outlet side of the freezing chamber expansion valve 15. The hot side radiator 24 and the freezing chamber evaporator 17 are connected in series, and the refrigerant passing through the freezing chamber expansion valve flows into the freezing chamber evaporator 17 after passing through the hot side radiator 24.

As a second example, it is clear that the following structure may also be adopted: the hot-side radiator 24 is disposed at an outlet side of the freezing chamber evaporator 17, whereby the refrigerant passing through the freezing chamber evaporator 17 flows into the hot-side radiator 24.

As a third example, a structure in which the hot-side radiator 24 and the freezing compartment evaporator 17 are connected in parallel at the outlet end of the freezing compartment expansion valve 15 is not excluded.

The hot-side radiator 24 is an evaporator, but is provided for the purpose of cooling a heat generating surface of a thermoelectric module described later, not for heat exchange with cold air in a deep freezing chamber.

In each of the three examples described above for the method of arranging the evaporators, a combined system may be adopted in which the switching valve 13, the refrigerating room expansion valve 14, and the refrigerating room evaporator 16 are eliminated, and a first refrigerant circulation system including a refrigerating room cooling evaporator, a refrigerating room cooling expansion valve, a refrigerating room cooling condenser, and a refrigerating room cooling compressor is combined. Here, the condenser for constituting the first refrigerant circulation system and the condenser for constituting the second refrigerant circulation system may be separately provided, or a combined condenser, which is a condenser composed of a single body and does not mix refrigerants, may be provided.

On the other hand, in the refrigerant cycle system of the refrigerator including the deep freezing chamber to form two storage chambers, only the first refrigerant cycle system may be provided.

Hereinafter, as an example, a description will be given of a configuration in which the hot-side radiator and the freezing compartment evaporator 17 are connected in series.

A condensing fan 121 is installed at a position adjacent to the condenser 12, a refrigerating compartment fan 161 is installed at a position adjacent to the refrigerating compartment evaporator 16, and a freezing compartment fan 171 is installed at a position adjacent to the freezing compartment evaporator 17.

On the other hand, inside the refrigerator having the refrigerant cycle system according to the embodiment of the present invention, there are formed: a refrigerating compartment maintained at a refrigerating temperature by cold air generated by the refrigerating compartment evaporator 16; a freezing chamber maintained at a freezing temperature using cold air generated by the freezing chamber evaporator 16; and a deep freezing chamber (deep freezing chamber) 202 that maintains a temperature of an ultra low temperature (cryogenic) or an ultra low temperature (ultra freezing) using a thermoelectric module to be described later. The refrigerating chamber and the freezing chamber may be adjacently disposed in an up-down direction or a left-right direction, and separated from each other by a partition wall. The deep freezing chamber may be provided at one side of the inside of the freezing chamber, but the present invention includes a case where the deep freezing chamber is provided at one side of the outside of the freezing chamber. In order to block the cold air of the deep freezing chamber and the cold air of the freezing chamber from exchanging heat with each other, the deep freezing chamber 202 may be partitioned from the freezing chamber by a deep freezing case 201 having high heat insulation performance.

In addition, the thermoelectric module may include: a thermoelectric element 21 having a characteristic that one side absorbs heat and the opposite side releases heat when power is supplied to the thermoelectric element 21; a cold-side heat sink (cold sink)22 mounted to a heat absorbing surface of the thermoelectric element 21; a hot-side heat sink (heat sink) mounted to a heat generating face of the thermoelectric element; and an insulating material 23 for blocking heat exchange between the cold side radiator 22 and the hot side radiator.

Here, the hot-side heat sink 24 is an evaporator that is in contact with the heat generating surface of the thermoelectric element 21. That is, the heat transferred to the heat generating surfaces of the thermoelectric elements 21 exchanges heat with the refrigerant flowing through the inside of the hot-side radiator 24. The refrigerant flowing along the inside of the hot-side radiator 24 and absorbing heat from the heat generating surfaces of the thermoelectric elements 21 flows into the freezing compartment evaporator 17.

In addition, a cooling fan may be provided in front of the cold-side radiator 22, and the cooling fan may be disposed at a rear side of the interior of the deep freezing chamber, and thus may be defined as a deep freezing chamber fan 25.

The cold-side radiator 22 is disposed behind the interior of the deep freezing chamber 202 and is configured to be exposed to cold air in the deep freezing chamber 202. Therefore, if the cold air of the deep freezing chamber 202 is forcibly circulated by driving the deep freezing chamber fan 25, the cold-side radiator 22 functions to transfer the absorbed heat to the heat absorbing surface of the thermoelectric element 21 after absorbing the heat by heat exchange with the cold air of the deep freezing chamber. The heat transferred to the heat absorbing surface is transferred to the heat emitting surface of the thermoelectric element 21.

The hot-side heat sink 24 functions to absorb heat again, which is absorbed from the heat absorbing surface of the thermoelectric element 21 and transferred to the heat generating surface of the thermoelectric element 21, and then to be discharged to the outside of the thermoelectric module 20.

Fig. 2 is a perspective view showing the structures of a freezing chamber and a deep freezing chamber of a refrigerator according to an embodiment of the present invention, and fig. 3 is a longitudinal sectional view taken along line 3-3 of fig. 2.

Referring to fig. 2 and 3, a refrigerator according to an embodiment of the present invention includes: an inner case 101 defining a freezing chamber 102; and a deep freezing unit 200 installed at one side of the inside of the freezing chamber 102.

In detail, the inside of the refrigerating chamber is maintained at about 3 ℃, the inside of the freezing chamber 102 is maintained at about-18 ℃, and the temperature of the inside of the deep freezing unit 200, i.e., the inside temperature of the deep freezing chamber 202, needs to be maintained at about-50 ℃. Therefore, in order to maintain the internal temperature of the deep freezing chamber 202 at a very low temperature of-50 ℃, an additional freezing device such as the thermoelectric module 20 is required in addition to the freezing chamber evaporator.

In more detail, the deep freezing unit 200 includes: a deep freezing casing 201 in which a deep freezing chamber 202 is formed; a deep freezing chamber drawer 203 slidably inserted into the interior of the deep freezing casing 201; and a thermoelectric module 20 mounted on a rear surface of the deep freezing case 201.

Instead of using the deep freezing chamber drawer 203, a deep freezing chamber door may be connected to a front side of the deep freezing case 201, and the entire inside of the deep freezing case 201 may be configured as a food storage space.

In addition, the rear surface of the inner case 101 is stepped toward the rear, thereby forming a freezing-evaporating chamber 104 for receiving the freezing chamber evaporator 17. In addition, the inner space of the inner case 101 is partitioned into the freezing and evaporating chamber 104 and the freezing chamber 102 by a partition wall 103. The thermoelectric module 20 is fixedly attached to the front surface of the partition wall 103, and a part of the thermoelectric module 20 penetrates the deep freezing casing 201 and is accommodated in the deep freezing chamber 202.

In detail, as described above, the hot-side radiator 24 for constituting the thermoelectric module 20 may be an evaporator connected to the freezing chamber expansion valve 15. A space for accommodating the hot-side heat sink 24 may be formed in the partition wall 103.

Is cooled to about-18 to-20 c while passing through the freezing chamber expansion valve 15? Flows inside the hot-side radiator 24, so that the surface temperature of the hot-side radiator 24 is maintained at-18 to-20 ℃? . Here, it should be apparent that the temperature and pressure of the refrigerant passing through the freezing compartment expansion valve 15 may become different according to the freezing compartment temperature condition.

When the front surface of the hot-side heat sink 24 is in contact with the rear surface of the thermoelectric element 21 and power is applied to the thermoelectric element 21, the rear surface of the thermoelectric element 21 is formed as a heat-generating surface.

When the cold-side heat sink 22 is in contact with the front surface of the thermoelectric element 40 and power is applied to the thermoelectric element 21, the front surface of the thermoelectric element 21 is formed as a heat absorbing surface.

The cold side heat sink 22 may include: a heat-conducting plate made of an aluminum material; and a plurality of heat exchange fins (fin) extending from the front surface of the heat conductive plate, which may extend vertically and be disposed to be spaced apart in a lateral direction.

Here, in the case where a case for surrounding or accommodating at least a part of a heat conductor composed of a heat conductive plate and heat exchange fins is provided, the cold-side heat sink 22 should be interpreted as including not only the heat conductor but also a heat transfer member of the case. The same applies to the hot-side heat sink 24, which hot-side heat sink 24 is to be understood not only as a heat conductor consisting of a heat conducting plate and heat exchange fins, but also, in the case of a housing, as a heat transfer component comprising a housing.

The deep freezing chamber fan 25 is disposed in front of the cold-side radiator 22, and the air inside the deep freezing chamber 202 is forcibly circulated.

The efficiency and cooling capacity of the thermoelectric element will be described below.

The efficiency Of the thermoelectric module 20 may be defined as a Coefficient Of Performance (COP), and the efficiency equation is as follows.

Q_c: cooling Capacity (Capacity to absorb Heat)

P_e: input (Input Power, Power supplied to the thermoelectric element)

P_e＝V×i

In addition, the cooling capacity of the thermoelectric module 20 is defined as follows.

< coefficient of characteristics of semiconductor Material >

α: seebeck (Seebeck) coefficient [ V/K ]

ρ: resistivity [ omega m-1]

k: thermal conductivity [ W/mk ]

< semiconductor Structure characteristics >

L: thickness of thermoelectric element: distance between heat absorbing surface and heat generating surface

A: area of thermoelectric element

< conditions for System use >

i: electric current

V: voltage of

Th: temperature of heat generating surface of thermoelectric element

Tc: temperature of heat absorbing surface of thermoelectric element

In the above cooling capacity equation, the first term on the right side may be defined as a Peltier Effect (Peltier Effect), and may be defined as a moving heat quantity between both ends of the heat absorbing surface and the heat generating surface caused by the voltage difference. The peltier effect increases as a function of current, in proportion to the supply current.

In the formula V ═ iR, the semiconductor used to constitute the thermoelectric element functions as a resistance, and the resistance can be regarded as a constant, so it can be said that the voltage and the current are in a proportional relationship. That is, when the voltage applied to the thermoelectric element 21 is increased, the current is also increased. The peltier effect can therefore be seen as a function of current, but also as a function of voltage.

The cooling capacity can also be regarded as a function of the current or as a function of the voltage. The peltier effect acts as a positive effect for increasing the cooling capacity. That is, if the supply voltage becomes large, the peltier effect increases, and the cooling capacity increases.

In the cooling capacity formula, the second term is defined as Joule Effect (Joule Effect).

The joule effect is an effect that generates heat when a current is applied to the resistor. In other words, heat is generated if power is supplied to the thermoelectric element, and thus it has a negative effect of reducing cooling capacity. Therefore, if the voltage supplied to the thermoelectric element is increased, the joule effect is increased, and the cooling capability of the thermoelectric element is reduced.

In the cooling capacity equation, the third term is defined as Fourier Effect.

The fourier effect is an effect in which heat moves by heat conduction when a temperature difference occurs between both surfaces of the thermoelectric element.

In detail, the thermoelectric element includes: a heat absorbing surface and a heat emitting surface formed of a ceramic substrate; and a semiconductor disposed between the heat absorbing surface and the heat generating surface. When a voltage is applied to the thermoelectric element, a temperature difference occurs between the heat absorbing surface and the heat generating surface. The heat absorbed by the heat absorbing surface passes through the semiconductor and is transferred to the heat generating surface. However, when a temperature difference occurs between the heat absorbing surface and the heat generating surface, heat flows back from the heat generating surface to the heat absorbing surface by heat conduction, and this phenomenon is referred to as a fourier effect.

Like the joule effect, the fourier effect also acts as a negative effect to reduce the cooling capacity. In other words, when the supply current increases, the temperature difference (Th-Tc) between the heat emitting surface and the heat absorbing surface of the thermoelectric element, that is, the Δ T value increases, and the cooling capability decreases as a result.

Referring to fig. 4, the fourier effect may be defined as a function of the temperature difference between the heat absorbing surface and the heat emitting surface, i.e., Δ T.

Specifically, when the specification of the thermoelectric element is determined, the k value, the a value, and the L value in the fourier effect term of the cooling capacity equation are constant values, and therefore the fourier effect can be regarded as a function having Δ T as a variable.

Therefore, as Δ T increases, the fourier effect value increases, but the fourier effect has a negative effect on the cooling capacity, and as a result, the cooling capacity will decrease.

As shown in the graph of fig. 4, it is understood that the larger Δ T is, the smaller the cooling capacity is under the condition that the voltage is constant.

In addition, in a state where Δ T has been set, for example, if it is defined that Δ T is 30 ℃ and a change in cooling capacity based on a change in voltage is observed, a parabolic form will be exhibited, that is, as the voltage value increases, the cooling capacity increases, and thereafter, a maximum value appears at a certain point, and then, it again decreases.

Here, it should be clear that since the voltage and the current are proportional, the current described in the cooling capacity equation may be interpreted as the voltage and the same manner.

In detail, as the supply voltage (or current) increases, the cooling capacity increases, which can be explained in the above cooling capacity formula. First, since the Δ T value has been set, it is formed as a constant. Since the Δ T value of the thermoelectric element per specification is determined, an appropriate specification of the thermoelectric element can be set according to the required Δ T value.

Since Δ T has been set, the fourier effect can be regarded as a constant, and as a result, the cooling capacity can be simplified as a function of the peltier effect, which can be regarded as a primary function of voltage (or current), and the joule effect, which can be regarded as a secondary function of voltage (or current).

As the voltage value gradually increases, the increase in the peltier effect as a primary function of the voltage is larger than the increase in the joule effect as a secondary function of the voltage, and as a result, the cooling capacity assumes an increased state. In other words, until the cooling capacity reaches a maximum, the function of the joule effect approaches a constant, whereby the cooling capacity takes a form close to a linear function of the voltage.

As the voltage further increases, a reverse phenomenon occurs in which the self-heating value due to the joule effect is larger than the moving heat value due to the peltier effect, and as a result, it is confirmed that the cooling capacity is again reduced. This can be understood more clearly by the relation between the peltier effect as a primary function of voltage (or current) and the joule effect as a function of the second order function of voltage (or current). That is, when the cooling capacity is reduced, the cooling capacity takes a form close to a quadratic function of voltage.

In the graph of fig. 4, it can be confirmed that the cooling capacity is maximized when the supply voltage is in the interval ranging from about 30V to 40V, more particularly, about 35V. Therefore, if only the cooling capacity is taken into consideration, it can be said that it is preferable to generate a voltage difference in the range of 30V to 40V in the thermoelectric element.

Referring to fig. 5, it can be confirmed that the greater the Δ T with respect to the same voltage, the lower the efficiency. This is a natural consequence, as efficiency is proportional to cooling capacity.

In addition, in a state where Δ T has been fixed, for example, if it is defined that Δ T is 30 ℃ and a change in efficiency based on a voltage change is observed, the following state will be exhibited: as the supply voltage increases, the efficiency also increases together, and then at a certain point of time, the efficiency decreases instead. It can be said that this is similar to a graph of cooling capacity based on voltage variation.

Here, the efficiency (COP) is not only a function of the cooling capacity but also a function of the input power, and if the resistance of the thermoelectric element 21 is regarded as a constant, the input (Pe) is formed as V²As a function of (c). If the cooling capacity is divided by V²Efficiency can finally be expressed as

Thus, it can be seen that the graph of the efficiency takes the form shown in fig. 5.

In the graph of fig. 5, it can be confirmed that: the point where the efficiency is the greatest occurs in the region where the voltage difference (or supply voltage) applied to the thermoelectric element is substantially less than 20V. Therefore, if the required Δ T has been determined, it is preferable to apply an appropriate voltage in accordance with the Δ T, thereby maximizing the efficiency. That is, if the temperature of the hot-side heat sink and the set temperature of the deep freezing chamber 202 are determined, Δ T will be determined, and the optimum voltage difference applied to the thermoelectric element can be determined from the Δ T.

Fig. 6 is a graph showing a voltage-based cooling capacity versus efficiency.

Referring to fig. 6, as described above, a state is shown in which the cooling capacity and the efficiency both increase and then decrease as the voltage difference increases.

In detail, it can be seen that the voltage value at which the cooling capacity is maximized and the voltage value at which the efficiency is maximized are different, which can be seen because the cooling capacity is a linear function of the voltage until the maximum is reached and the efficiency is a quadratic function of the voltage.

As shown in fig. 6, for example, it was confirmed that, in the case of the thermoelectric element having a Δ T of 30 ℃, the efficiency of the thermoelectric element was the highest in the range of about 12V to 17V of the voltage difference applied to the thermoelectric element. In the range of the voltage, the cooling capacity exhibits a state of continuing to increase. Therefore, it is understood that a voltage difference of at least 12V or more is required in consideration of the cooling capacity, and the efficiency is the highest when the voltage difference is 14V.

Hereinafter, the set temperature of each storage chamber is defined as a notch temperature (notch temperature) and will be described. The reference temperature line may also be denoted as a critical temperature line.

In the graph, the reference temperature line on the lower side is a reference temperature line for distinguishing the satisfied temperature region from the unsatisfied temperature region. Therefore, the lower region a of the lower reference temperature line may be defined as a satisfied section or a satisfied region, and the upper region B of the lower reference temperature line may be defined as a non-satisfied section or a non-satisfied region.

In addition, the reference temperature line on the upper side is a reference temperature line for distinguishing the region not satisfying the temperature and the upper limit temperature region. Therefore, the upper region C of the upper reference temperature line may be defined as an upper limit region or an upper limit section, and may be regarded as a special operating region.

On the other hand, when defining the satisfied/unsatisfied/upper limit temperature area for controlling the refrigerator, the lower reference temperature line may be defined as any one of a case of being included in the satisfied temperature area and a case of being included in the unsatisfied temperature area. In addition, the upper reference temperature line may be defined as one of a case included in the non-temperature-satisfying region and a case included in the upper limit temperature region.

When the temperature inside the refrigerator is in the satisfaction region a, the compressor is not driven, and when the temperature inside the refrigerator is in the non-satisfaction region B, the temperature inside the refrigerator is brought into the satisfaction region by driving the compressor.

In addition, the case where the temperature of the inside of the refrigerator is in the upper limit region C may be regarded as a case where the load of the inside of the refrigerator is sharply increased due to the food having a high temperature being put into the inside of the refrigerator or the door of the corresponding storage chamber being opened, whereby a special operation algorithm including a load coping operation may be performed.

Fig. 7 (a) is a diagram illustrating a reference temperature line for controlling the refrigerator according to a variation in the temperature of the refrigerating compartment.

The grade temperature N1 of the refrigerating compartment is set to a temperature above zero. Further, in order to maintain the temperature of the refrigerating compartment at the class temperature N1, the compressor driving is controlled when the temperature rises to the first satisfied critical temperature N11 higher than the class temperature N1 by the first temperature difference d1, and the compressor is stopped when the temperature falls to the second satisfied critical temperature N12 lower than the class temperature N1 by the first temperature difference d1 after the compressor is driven.

The first temperature difference d1 is a temperature value increased or decreased from the grade temperature N1 of the refrigerating compartment, and the first temperature difference d1 may be defined as a control difference (control differential) or a control temperature difference (control differential temperature) for defining a temperature interval regarded as the refrigerating compartment temperature being maintained at the grade temperature N1 as a set temperature, and the first temperature difference d1 may be approximately 1.5 ℃.

If it is determined that the temperature of the refrigerating compartment has increased from the class temperature N1 to the first unsatisfied critical temperature N13 higher than the second temperature difference d2, the control is performed so as to execute the special operation algorithm. The second temperature difference d2 may be 4.5 ℃. The first unsatisfied critical temperature may also be defined as an upper input temperature.

If the temperature of the inside of the refrigerator drops to a second unsatisfied temperature N14 lower than the first unsatisfied critical temperature by a third temperature difference d3 after the execution of the special operation algorithm, the operation of the special operation algorithm is ended. The second unsatisfied temperature N14 is lower than the first unsatisfied temperature N13, and the third temperature difference d3 may be 3.0 ℃. The second unsatisfied critical temperature N14 may be defined as an upper limit release temperature.

After the special operation algorithm is finished, the temperature inside the refrigerator reaches the second satisfied critical temperature N12 by adjusting the cooling capacity of the compressor, and then the driving of the compressor is stopped.

Fig. 7 (b) is a graph showing a reference temperature line for controlling the refrigerator according to a variation in the temperature of the freezing chamber.

The form of the reference temperature line for controlling the temperature of the freezing compartment is the same as that of the reference temperature line for controlling the temperature of the refrigerating compartment except that the grade temperature N2 and the temperature variation amounts k1, k2, and k3, which are increased or decreased from the grade temperature N2, are different from the grade temperature N1 and the temperature variation amounts d1, d2, and d3 of the refrigerating compartment.

As described above, the freezing compartment grade temperature N2 may be-18 ℃, but is not limited thereto. The control temperature difference k1 for defining a temperature interval, which is regarded as the temperature of the freezing chamber being maintained at the class temperature N2 as the set temperature, may be 2 ℃.

Therefore, when the freezer temperature rises to the first satisfied threshold temperature N21 higher than the rank temperature N2 by the first temperature difference k1, the compressor is driven, and when the first unsatisfied threshold temperature (upper limit input temperature) N23 higher than the rank temperature N2 by the second temperature difference k2, the special operation algorithm is executed.

After the compressor is driven, if the freezing compartment temperature drops to the second satisfied critical temperature N22, which is lower than the rank temperature N2 by the first temperature difference k1, the driving of the compressor is stopped.

After the execution of the special operation algorithm, if the freezing compartment temperature drops to the second unsatisfied critical temperature (upper limit releasing temperature) N24, which is lower than the first unsatisfied temperature N23 by the third temperature difference k3, the execution of the special operation algorithm is ended. The freezer compartment temperature is reduced to a second, meeting critical temperature N22 by adjusting the compressor cooling capacity.

On the other hand, even in a state where the deep freezing chamber mode has been turned off, it is necessary to intermittently control the temperature of the deep freezing chamber at a predetermined cycle, thereby preventing the temperature of the deep freezing chamber from excessively increasing. Therefore, in a state where the deep freezing chamber mode has been turned off, the temperature control of the deep freezing chamber follows the temperature reference line for controlling the temperature of the freezing chamber shown in (b) of fig. 7.

As described above, the reason why the reference temperature line for controlling the freezing chamber temperature is applied in the state where the deep freezing chamber mode has been turned off is because the deep freezing chamber is located inside the freezing chamber.

That is, even when the deep freezer mode is closed and the deep freezer is not used, the internal temperature of the deep freezer needs to be maintained at least at the same level as the freezer temperature to prevent the load of the freezer from increasing.

Therefore, in a state where the deep freezing chamber mode has been closed, the gradation temperature of the deep freezing chamber is set to be the same as the gradation temperature N2 of the freezing chamber, whereby the first and second satisfied critical temperatures and the first and second unsatisfied critical temperatures are also set to be the same as the critical temperatures N21, N22, N23, N24 for controlling the freezing chamber temperature.

Fig. 7 (c) is a diagram showing a reference temperature line for controlling the refrigerator according to a temperature change of the deep freezing chamber in a state where the deep freezing chamber mode has been turned on.

In a state where the deep freezing chamber mode has been turned on, that is, in a state where the deep freezing chamber is turned on, the grade temperature N3 of the deep freezing chamber is set to a temperature significantly lower than the grade temperature N2 of the freezing chamber, which may be about-45 ℃ to-55 ℃, and may preferably be-55 ℃. In this case, it can be said that the deep freezing chamber graded temperature N3 corresponds to the temperature of the heat absorbing surface of the thermoelectric element 21, and the freezing chamber graded temperature N2 corresponds to the temperature of the heat generating surface of the thermoelectric element 40.

Since the refrigerant passing through the freezing compartment expansion valve 15 passes through the hot-side radiator 24, the temperature of the heat generating surface of the thermoelectric element 40 contacting the hot-side radiator 24 is maintained at least to a temperature corresponding to the temperature of the refrigerant passing through the freezing compartment expansion valve. Therefore, the temperature difference between the heat absorbing surface and the heat generating surface of the thermoelectric element 40, i.e., Δ T, is 32 ℃.

On the other hand, the control temperature difference m1 for defining the temperature interval, i.e., the deep-freezing chamber control temperature difference, may be set higher than the freezing chamber control temperature difference k1, which may be 3 ℃ as an example, the temperature interval is regarded as the deep-freezing chamber being maintained at the level temperature N3 as the set temperature.

Therefore, it can be said that the set temperature holding section defined as the section between the first satisfying critical temperature N31 and the second satisfying critical temperature N32 of the deep freezing chamber is wider than the set temperature of the freezing chamber as the holding section.

Further, the special operation algorithm is executed when the temperature of the deep freezing chamber rises to a first unsatisfied critical temperature N33 higher than the rank temperature N3 by a second temperature difference m2, and the execution of the special operation algorithm is ended when the temperature of the deep freezing chamber drops to a second unsatisfied critical temperature N34 lower than the first unsatisfied critical temperature N33 by a third temperature difference m3 after the execution of the special operation algorithm. The second temperature difference m2 may be 5 ℃.

Here, the second temperature difference m2 of the deep freezing chamber is set to be higher than the second temperature difference k2 of the freezing chamber. In other words, the interval between the first unsatisfied critical temperature N33 for controlling the temperature of the deep freezing chamber and the grade temperature N3 of the deep freezing chamber is set to be greater than the interval between the first unsatisfied critical temperature N23 for controlling the temperature of the freezing chamber and the freezing chamber grade temperature N2.

This is because the internal space of the deep freezing chamber is smaller than the freezing chamber, and the heat insulating performance of the deep freezing case 201 is more excellent, and therefore, the amount of heat load input into the deep freezing chamber released to the outside is small. Furthermore, the temperature of the deep freezing chamber is significantly lower than that of the freezing chamber, and therefore, when a heat load such as food penetrates into the inside of the deep freezing chamber, the sensitivity to the reaction to the heat load is very high.

Thus, in the case where the second temperature difference m2 of the deep freezing chamber is set to be the same as the second temperature difference k2 of the freezing chamber, the execution frequency of a special operation algorithm such as a load-coping operation may become excessively high. Therefore, in order to reduce the frequency of execution of the special operation algorithm and reduce the power consumption, it is preferable to set the second temperature difference m2 of the deep freezing chamber to be greater than the second temperature difference k2 of the freezing chamber.

On the other hand, a control method of a refrigerator according to an embodiment of the present invention will be described below.

Hereinafter, the content of executing a specific step if at least any one of a plurality of conditions is satisfied should be interpreted as meaning that the specific step is executed if any one of a plurality of the conditions is satisfied at the point of time when the control section makes the judgment, and in addition, the specific step is executed only if any one or a part of the plurality of conditions is satisfied, or if all of the conditions must be satisfied.

In detail, the flowchart disclosed in fig. 8 shows a control method of the freezing chamber load coping operation in the case where the deep freezing chamber mode is in the on state, and the flowchart disclosed in fig. 9 shows a control method of the freezing chamber load coping operation in the case where the deep freezing chamber mode is in the off state.

The deep freezing chamber mode is in the on state, that is, the user presses the deep freezing chamber mode implementing button, so that the deep freezing chamber mode is in the executable state. Therefore, when the deep freezing chamber mode is in the on state, if a specific condition is satisfied, power can be immediately applied to the thermoelectric module.

In contrast, the deep freezer mode being in the off state means that the power supply to the thermoelectric module is in a state of being cut off. Thus, power is not supplied to the thermoelectric module and the deep freezer fan, except for exceptions.

First, referring to fig. 8, the control unit determines whether the current state is the deep freezer mode on state (S110). If it is determined that the current deep freezer mode is in the off state, the process goes to step D, which will be described in detail with reference to fig. 9.

Specifically, if it is determined that the current deep freezer mode is in the on state, the control unit determines whether or not the current state satisfies the "first freezer compartment load coping operation input condition" (S210).

The "first freezer compartment load coping operation input condition" is a load coping operation condition for inputting a load to the freezer compartment in the open state of the deep freezer compartment mode and for quickly removing the freezer compartment load.

As an example, the "first freezing compartment load coping operation input condition" may include: the freezing chamber temperature is at the set time t after the freezing chamber door is closed_aWithin rises to a set temperature T_aThe case (1). The set time t_aMay be 210 seconds, but is not limited thereto, the set temperature T_aMay be 2 c, but is not limited thereto.

If the "first freezing room load coping operation input condition" is satisfied, it is determined whether or not an indoor temperature Zone (RT Zone) to which the current indoor temperature belongs corresponds to a Zone other than the high temperature Zone (S220). That is, it is determined whether or not an indoor temperature Zone (RT Zone) to which the current indoor temperature belongs to a medium temperature Zone or a low temperature Zone.

In detail, the control part may store a lookup table divided into a plurality of indoor Temperature zones (RT zones) according to an indoor Temperature range. For example, as shown in table 1 below, the indoor temperature range may be subdivided into 8 indoor temperature zones (RT zones), but the present invention is not limited thereto.

[ Table 1]

In more detail, a temperature range region where the indoor temperature is the highest may be defined as RT Zone 1 (or Z1), a temperature range region where the indoor temperature is the lowest may be defined as RT Zone 8 (or Z8), Z1 may be mainly regarded as an indoor state in summer, and Z8 may be regarded as an indoor state in winter.

In addition, the indoor temperature regions may be grouped and classified into a large classification, a medium classification, and a small classification form. For example, as shown in table 1 above, the indoor temperature region may be defined as a low temperature region, a middle temperature region (or comfort region), and a high temperature region according to a temperature range.

If it is determined that the region (RT Zone) to which the current indoor temperature belongs corresponds to the high temperature region and does not correspond to the low temperature region and the medium temperature region, control is returned to the initial step S110 without performing the freezer load handling operation.

The reason for excluding the case where the current indoor temperature is a high temperature region may be that the operation rate of the freezing chamber fan is relatively high, so that the possibility of frost being generated on the outer wall of the deep freezing chamber is low. However, the load coping operation of the freezing chamber of the present invention may not limit the indoor temperature. That is, it is not excluded to omit step S220.

On the other hand, although the current deep freezer mode is in the on state, if it is determined that the current state is a state in which the "first freezer compartment load coping operation input condition" is not satisfied, it goes to step E and performs the "freezer compartment fan output control in which the deep freezer mode is in the on state", which will be described in detail with reference to fig. 10.

If the "first freezing room load coping operation input condition" is satisfied and it is determined that the indoor temperature is the temperature of the middle temperature region or the low temperature region, the control part performs a process of determining whether the "refrigerating room load coping operation input condition" is satisfied (S230).

As with the "freezer compartment load coping operation condition", the "refrigerator compartment load coping operation input condition" may be set as appropriate in consideration of various conditions including an operation condition, a refrigerator compartment installation space condition, and the like.

For example, the "refrigerating compartment load coping operation input condition" may include a set time t after the refrigerating compartment temperature is closed_bThe inner temperature of the refrigerator door is increased by a set temperature T compared with the temperature of the refrigerating chamber before the refrigerator door is opened_bThe above is the case. Here, a time t is set_bMay be 5 minutes, but is not limited thereto, and the set temperature T_bMay be 2 c, but is not limited thereto.

When the "refrigerating room load coping operation input condition" is satisfied, the situation of the refrigerating room load coping operation and the situation of the freezing room load coping operation occur simultaneously, and it can be said that the conflict of the load coping operation occurs.

If the load-handling operation of the refrigerating compartment conflicts with the load-handling operation of the freezing compartment, the control unit preferentially executes the load-handling operation of the refrigerating compartment. This is a control method based on a load refrigerator, in which cooling is performed from a storage chamber satisfying a higher temperature inside the refrigerator first, and then the storage chamber satisfying a lower temperature inside the refrigerator is cooled. If cooling is first performed from the storage chamber satisfying the lower temperature, the temperature of the storage chamber satisfying the higher temperature will rapidly rise to increase the possibility of spoiling the stored food.

For this reason, when the freezer load operation and the refrigerator load operation are simultaneously performed or conflict with each other with the time difference therebetween, the control is performed to suspend (pause) the freezer load operation (S240). The stop of the operation of the freezer load handling means that the freezer valve is closed so that the refrigerant cannot flow to the freezer evaporator side. Here, the operation for coping with the load of the freezing chamber is suspended including maintaining the suspension state.

In other words, in the refrigerant cycle system shown in fig. 1, the opening degree of the switching valve 13 is adjusted to control the refrigerant to flow only to the refrigerating chamber expansion valve 14. Here, the operation of preventing the refrigerant from flowing to the freezing-chamber expansion valve 15 by adjusting the opening degree of the switching valve 13 may be defined as "freezing-chamber valve closed". In contrast, the action of preventing the refrigerant from flowing to the refrigerating chamber expansion valve 14 by adjusting the opening degree of the switching valve 13 may be defined as "refrigerating chamber valve closed".

On the other hand, in the state where the freezer load coping operation is stopped, the freezer fan is controlled to be driven at the second speed while the refrigerator load coping operation is put into operation (S250).

When the refrigerating chamber load-handling operation is started, the refrigerating chamber valve is opened and the refrigerating chamber fan is rotated at a high speed. When the refrigerating room temperature enters the satisfactory temperature range shown in fig. 7 (a) or the maximum operation time elapses, the control may be performed so as to end the refrigerating room load handling operation. The maximum operation time may be 1 hour, but is not limited thereto.

Specifically, in the conventional technology, when the operation to cope with the load of the freezing chamber is stopped, the freezing chamber valve is closed and the driving of the freezing chamber fan is also controlled to be stopped. However, according to the present invention, the freezing compartment fan is rotated at the second speed even if the freezing compartment valve is in the closed state while the refrigerating compartment load coping operation is performed.

Then, as the cool air of the freezing chamber circulates, the moisture generated inside the freezing chamber may be discharged to the freezing evaporation chamber by a load input into the freezing chamber. Since the cold air of the freezing chamber is circulated, there is also an effect of reducing the possibility of moisture adhering to the outer wall of the deep freezing chamber.

It is to be understood that the second speed may be a low speed, but is not limited thereto.

While the refrigerating room load coping operation is being executed, the control unit continues to determine whether or not the refrigerating room temperature enters a satisfied temperature region a shown in fig. 7 (a) (S260).

If it is determined that the temperature of the refrigerating chamber has entered the temperature-satisfying region a, any one of the following three control methods is executed.

As a first method (first), when the refrigerating room temperature enters the satisfied temperature region a, the refrigerating room load handling operation is terminated, and the refrigerating room fan controlled to rotate at the second speed is also stopped while the refrigerating room valve is closed and the refrigerating room fan is stopped.

Furthermore, the freezer load handling operation is released (S270), and the freezer load handling operation algorithm of the present embodiment is terminated. Then the interrupted or remaining load coping operation of the freezing chamber is no longer performed and is returned to the normal operation state before the load coping operation.

As a second method (ii), when the refrigerating room temperature enters the satisfied temperature region a, the refrigerating room load handling operation is ended, and the algorithm of the present embodiment may be returned to the initial step, thereby determining whether or not the first freezing room load handling operation input condition is satisfied again. In this case, even if the refrigerating room load coping operation is ended, the freezing room fan can be maintained at the second speed, and whether or not the "first freezing room load coping operation input condition" is satisfied can be determined again. That is, after the refrigerating room load handling operation is ended, the control may be returned to any one of step S110 and step S210.

As a third method (c), when the temperature of the refrigerating chamber falls within the temperature-satisfying range, the refrigerating chamber load coping operation is terminated. The freezer load coping operation temporarily suspended in the step S240 can be immediately continued without the process of re-judgment performed in the first and second methods. That is, the speed of the freezing chamber fan can be changed from a low speed to a medium speed.

On the other hand, if the "refrigerating room load coping operation input condition" is not satisfied (S230), only the freezing room load coping operation is input alone (S280).

In detail, the freezing compartment load coping operation may be defined as an operation of opening a freezing compartment valve, thereby flowing refrigerant to the freezing compartment evaporator 15, and rotating the freezing compartment fan 171 at a first speed. The first speed may be a medium speed, but is not limited thereto.

For reference, it is preferable to supply a minimum voltage to the thermoelectric element during the execution of the freezing compartment load coping operation. Then, it is possible to minimize heat exchange between the refrigerant flowing through the freezing chamber expansion valve 15 and the heat generating surfaces of the thermoelectric elements and to increase heat exchange with the cold air of the freezing chamber, so that it is possible to minimize the time required to cool the freezing chamber.

In addition, by operating the thermoelectric element, it is possible to prevent the heat load of the freezing and evaporating chamber from penetrating into the deep freezing chamber using the thermoelectric module as a heat transfer medium.

While the freezing compartment load coping operation is being executed, the control unit continuously determines whether or not the temperature of the refrigerating compartment has increased to the upper limit temperature (S290). Here, the case where the temperature of the refrigerating chamber rises to the upper limit temperature means a case where the temperature of the inside of the refrigerator naturally rises to be higher than the upper limit input temperature, and is not a case where the load infiltration occurs when the refrigerating chamber door is opened.

If it is determined that the refrigerating room temperature has entered the upper limit region C shown in fig. 7 (b) (has increased to the upper limit input temperature or more) while the freezing room load coping operation is being performed, the operation is switched to the simultaneous operation for cooling the refrigerating room and the freezing room at the same time (S300).

During the period in which the simultaneous operation is performed, the refrigerating chamber fan and the freezing chamber fan may be controlled to be rotated at the first speed, but are not necessarily limited thereto. Even if the freezer load coping operation condition is satisfied during the execution of the simultaneous operation, it is possible to control not to execute the freezer load coping operation.

Further, the freezer load responding operation can be canceled (S270) when at least one of the condition that the temperature of the refrigerating room enters the temperature range a (S310) shown in fig. 7 (a) and the condition that the temperature of the freezing room enters the temperature range a (S311) shown in fig. 7 (b) is satisfied. That is, even when the temperatures of the refrigerating room and the freezing room enter the satisfactory temperature range at the same time, the load coping operation of the freezing room can be controlled to be cancelled.

Here, the fact that the freezing chamber load coping operation is released may be interpreted that the freezing chamber valve is closed and the freezing chamber fan is stopped, which means that the simultaneous operation mode is about to be ended.

The reason why the release of the freezer load countermeasure operation does not become a problem even if only the refrigerating room temperature enters the satisfactory temperature region is as follows. In detail, if the freezer compartment temperature load coping operation is released and the operation returns to the first step, a process of determining whether or not the first freezer compartment load coping operation input condition is satisfied is performed (S210). At this time, if the operation condition for coping with the load of the freezing chamber is not satisfied, the routine proceeds to step E, and the output control routine of the general freezing chamber fan is executed. Therefore, even if only the refrigerating compartment temperature is satisfied, the load handling operation of the freezing compartment can be canceled.

On the other hand, if the refrigerating compartment temperature is within the satisfied temperature region or the unsatisfied temperature region in step S290, the step of determining whether the freezing compartment temperature enters the satisfied temperature region is performed while the freezing compartment load handling operation is continued (S291).

Specifically, if it is determined that the freezer compartment temperature falls within the satisfied temperature range shown in fig. 7 (b), the routine naturally proceeds to the step of canceling the freezer compartment load handling operation (S270).

However, if the freezer compartment temperature does not reach the satisfactory temperature range, it is determined whether the freezer compartment load handling operation has elapsed the set time t₄(S292). If judged that the set time t has elapsed₄Then, even if the freezer compartment temperature does not enter the satisfactory temperature region a, the freezer compartment load handling operation is cancelled (S270).

If the set time t has not elapsed after the start of the execution of the load coping operation of the freezing chamber₄Even if the freezing compartment load coping operation is being executed, the control part performs a step of determining whether or not the refrigerating compartment load coping operation input condition is satisfied (S230). That is, it is determined whether or not a situation in which the load input operation conflicts occurs with a time difference, rather than a situation in which the load input operation conflicts simultaneously.

Here, it is not proposed that the freezer load coping operation occurs while the freezer load coping operation is performed first, because even if the situation of the freezer load coping operation occurs, the operation situation of the refrigerator does not change. That is, if the refrigerating room load coping operation is started first, the previous operation state is maintained even if the freezing room load coping operation occurs.

As described above, when the deep freezer mode is in the on state, since the deep freezer temperature is significantly lower than the freezer temperature, even if the region (RT Zone) to which the indoor temperature belongs is located in the low temperature region, frost is likely to be generated on the outer wall of the deep freezer due to the load applied from the outside. Therefore, the control method according to the embodiment of the present invention is characterized in that the input range of the freezing chamber load coping operation is extended to the indoor temperature range (RT Zone) of the low temperature range in the state where the deep freezing chamber mode is on.

On the other hand, if it is determined in step S110 of fig. 8 that the current deep freezing chamber mode is in the off state, the control routine of fig. 9 is executed.

Referring to fig. 9, the control unit determines whether or not the "second freezer compartment load coping operation input condition" is satisfied in the closed state of the deep freezer compartment mode (S410). In detail, the "second freezing compartment load coping operation input condition" may be set to be different from the "first freezing compartment load coping operation input condition".

For example, the temperature of the freezer compartment may be determined as the set time t after the freezer compartment door is closed_cIf the temperature exceeds the freezing compartment class temperature N2 or the temperature rises to the unsatisfactory temperature range, the second freezing compartment load handling operation input condition is satisfied. The set time t_cBut is not limited thereto, may be 3 minutes.

Here, the minimum value of the thermal load satisfying the "first freezing compartment load coping operation input condition" may be set to be lower than the minimum value of the thermal load satisfying the "second freezing compartment load coping operation input condition". In other words, the heat load satisfying the second freezing compartment load coping operation input condition will satisfy the first freezing compartment load coping operation input condition, but the heat load satisfying the first freezing compartment load corresponding input condition may not satisfy the second freezing compartment load corresponding input condition.

This is because the deep freezing chamber temperature is a very low temperature state in the open state of the deep freezing chamber mode, and the deep freezing chamber temperature is a freezing chamber temperature in the closed state of the deep freezing chamber mode. That is, when the deep freezing chamber mode is in the open state, even if the heat load input to the freezing chamber is relatively small, the frost is more likely to be generated on the outer wall of the deep freezing chamber than when the deep freezing chamber mode is in the closed state.

Therefore, even if the freezing chamber load coping operation is executed when the deep freezing chamber mode is in the open state under the condition that the amount of heat load penetrating into the freezing chamber is the same, the freezing chamber load coping operation may not be executed when the deep freezing chamber mode is in the closed state.

In addition, if the second freezer load coping operation input condition is not satisfied, the routine proceeds to step F, and the control method shown in fig. 11, which will be described later, is executed. The control method shown in fig. 11 is the content of the output control of the freezing chamber fan with the deep freezing chamber in the closed state.

If it is determined that the second freezer load coping operation input condition is satisfied, a step of determining whether or not the current indoor temperature belongs to the medium temperature region is performed (S220). Here, the freezer load coping operation is executed only when the indoor temperature belongs to the medium temperature region in the closed state of the deep freezing chamber, which is different from the freezer load coping operation input condition in the open state of the deep freezing chamber mode.

If the indoor temperature does not belong to the medium temperature range, the operation returns to the initial determination step (S110) without performing the load handling operation of the freezing chamber even if the input condition for the load handling operation of the freezing chamber is satisfied. That is, only when the indoor temperature belongs to the medium temperature range, the operation is controlled so as to be put into the load handling operation of the freezing chamber.

This is because, in the state where the deep freezer mode is off, the deep freezer temperature and the freezer compartment temperature are controlled to be substantially the same, and therefore, in the low temperature region, it is only necessary to perform a normal operation of the freezer compartment without putting the freezer compartment load handling operation into operation.

On the other hand, in the state where the second freezing room load coping operation input condition is satisfied (S410), if it is determined that the indoor temperature belongs to the medium temperature region (S420), the control unit performs a step of determining whether or not the refrigerating room load coping operation input condition is satisfied (S430), and if it is determined that the refrigerating room load coping operation input condition is satisfied, performs steps S440 to S470.

The contents of steps S440 to S470 are the same as those of steps S240 to S270 of fig. 8, and thus a repetitive description thereof will be omitted.

However, when the freezing room load coping operation and the refrigerating room load coping operation conflict with each other and the refrigerating room load coping operation is preferentially executed in a state where the deep freezing room is closed, if the refrigerating room temperature enters a satisfactory temperature range, the freezing room load coping operation is unconditionally released (S520). However, it is to be understood that the second method (performing the re-judgment process) and the third method (continuing the execution of the freezer load coping operation) illustrated in fig. 8 are not excluded.

In step S430, if it is determined that the conflict of the load handling operation does not occur because the refrigerating room load handling operation input condition is not satisfied, the freezing room load handling operation is executed (S480). The process after the freezing chamber load coping operation is started, that is, the contents of steps S490, S491, S492, S500, S510, S511, and S520 are the same as those of steps S290, S291, S292, S300, S310, S311, and S270 described in fig. 8, and therefore, a repetitive description thereof will be omitted.

However, after the freezing compartment load coping operation is released (S520), the control returns to the step for determining whether the second freezing compartment load coping operation input condition is satisfied (S410), but the control may return to the step for determining whether the deep freezing compartment mode is in the on state (S110). This is because, even in the case where the deep freezer mode is in the off state, there is a possibility that the deep freezer mode is selected during the execution of the freezer load handling operation.

Hereinafter, a method of controlling the output of the freezing chamber fan when the freezing chamber load coping operation is not generated in the open state of the deep freezing chamber mode will be described.

In detail, in the state where the deep freezing chamber mode is opened, even if the freezing chamber is located in the temperature satisfying region, the refrigerant is made to flow through the freezing chamber evaporator to cool the deep freezing chamber, and as a result, the cold air in the freezing evaporation chamber permeates into the freezing chamber, and the cold air of the freezing chamber may sink. If the cold air sinking phenomenon occurs, the temperature of the upper space and the lower space inside the freezing chamber may become uneven.

The control method disclosed in fig. 10 may be summarized as a control method for preventing such a cold air sinking phenomenon of the freezing chamber.

Referring to fig. 10, if it is determined that the current deep freezer mode is in the on state, the control unit determines whether or not the current freezer compartment is in the non-operating state (S120).

Since the freezing compartment is located in the satisfied temperature region a shown in (b) of fig. 7, the operation of the freezing compartment may not be performed, and even if the freezing compartment is not located in the satisfied temperature region a, the operation of the freezing compartment may not be performed for other reasons including the refrigerating compartment separate operation mode.

Therefore, step S120 is to determine whether or not the freezing chamber is currently in the non-operating state regardless of whether or not the freezing chamber is located in the satisfied temperature region a.

If the freezing chamber is in the non-operating state, the freezing chamber fan 171 is stopped (S130). Here, the stop of the freezing chamber fan 171 includes not only the stop after the driving of the freezing chamber fan 171 but also the maintenance of the stopped state of the freezing chamber fan 171.

Next, the control portion determines whether or not an operation for preventing the cold air of the freezing chamber from sinking is to be performed by detecting the internal temperature of the freezing chamber. That is, the control part determines whether the freezing compartment temperature is in the satisfied temperature region (S140), and determines whether to perform an operation for preventing the cold air from sinking.

On the other hand, if it is determined that the freezing room is currently operating, at least one or more of the following processes is executed: a process of judging whether the freezing chamber door is opened (S121); judging whether the time elapsed after the start of the operation of the freezing chamber is at the set time t₁A process (S122); and judging whether the elapsed time after the door of the freezing chamber is closed is at the set time t₂The process (S123).

The set time t₁May be 90 seconds, but is not limited thereto, the set time t₂But is not limited to, 20 seconds.

In this case, it can be summarized that, when it is determined that the current deep freezing chamber mode is in the on state, the control unit controls the refrigerator to move to the step of stopping or maintaining the stop state of the freezing chamber fan (S130) if at least one of the determination processes of the steps S120, S121, S122, and S123 is satisfied. That is, this should be interpreted as including a case where the conditions of all of the steps S120, S121, S122, and S123 are satisfied.

It should be understood that, in the case of executing a plurality of processes among the processes of steps S121 to S123, the plurality of processes are executed in sequence, but the execution order is not limited.

If all the conditions for the determinations in steps S120, S121, S122, and S123 are not satisfied, the control proceeds to a step for determining which state the indoor temperature is in (S124).

In step S124, the control section determines which area the current state is in based on the indoor temperature of the refrigerator is set. As an example, it may be determined whether or not the Zone (RT Zone) to which the current indoor temperature belongs is located in a high temperature Zone. If it is determined that the temperature Zone (RT Zone) to which the current indoor temperature belongs to the high temperature Zone, the freezing compartment fan may be driven at the first speed (S125).

If it is determined that the current indoor temperature zone does not belong to the high temperature zone, the freezing compartment fan may be driven at the second speed (S126). The second speed may be a slower speed than the first speed.

While the freezing chamber fan is driven at the first speed or the second speed, the control part determines whether the freezing chamber temperature enters a satisfying temperature region a shown in fig. 7 (b) (S127).

If it is determined that the freezer temperature does not enter the satisfactory temperature range a, the process returns to the step of determining whether or not the deep freezer mode is in the on state (S110).

On the contrary, if it is judged that the temperature of the freezing chamber is reachedWhen the temperature area A is satisfied, the fan of the freezing chamber is enabled to be at the set time t₃Is driven at the third speed (S128, S129). The third speed may be a slower speed than the second speed. In detail, the first speed may be set to a high speed, the second speed may be set to a medium speed, and the third speed may be set to a low speed.

If the set time t has elapsed₃The freezing chamber fan is stopped (S130) and the process proceeds to a step for determining whether to perform an operation for preventing the cool air from sinking (S140 or less). In the step S140, since the freezing compartment temperature is within the satisfied temperature region, it can be said that the step S140 is a freezing compartment temperature determination process for determining whether to perform the operation of preventing the cold air from sinking.

That is, even during the period in which the freezing chamber is not operating, there may be a case in which the freezing chamber temperature is in an unsatisfactory state, and therefore, it is necessary to determine whether or not the freezing chamber temperature is within the satisfactory temperature region. For example, when a conflict occurs with another type of operation mode such as a refrigerating compartment operation alone, even if the freezing compartment temperature is not in the temperature satisfying region, there may be a case where the freezing compartment operation is not performed due to the priority of mode implementation.

On the other hand, if it is determined that the freezer compartment temperature is not within the temperature-satisfying range, the control returns to the step of determining whether or not the deep freezer compartment mode is on (S110). For example, if it is determined that the freezer compartment temperature does not enter the satisfactory temperature range while the freezer compartment fan is rotating at any one of the high speed, the medium speed, and the low speed to reduce the freezer compartment load, the process returns to the step of determining whether the deep freezer compartment mode is on (S110), and thereby repeatedly determines whether to stop the freezer compartment fan or to continue rotating the freezer compartment fan.

Here, it should be clear that if it is determined that the freezer compartment temperature does not enter the satisfactory temperature region, the control may be returned to any one of steps S120, S121, S122, S123, and S124, in addition to the method of returning to step S110.

On the other hand, if it is determined that the current freezer compartment temperature is within the satisfactory temperature range, it can be said that the first condition for executing the operation for preventing the cold air from sinking is satisfied.

If it is determined that the current freezer compartment temperature is within the satisfied temperature range, a step of determining whether or not the deep freezer compartment temperature is not less than the satisfied temperature corresponding to the second condition is performed (S150).

That is, a step for determining whether or not the deep freezing chamber temperature is not satisfied, that is, in the regions B and a shown in fig. 7 (B) is performed. This can be regarded as that the control of the freezing chamber fan for preventing the cold air from sinking of the present invention has the execution of the operation for cooling the deep freezing chamber as a condition, since the deep freezing chamber is in the region where the temperature is not satisfied.

If it is determined that the deep freezing chamber temperature is not equal to or higher than the temperature, it is determined whether or not the current indoor temperature corresponding to the third condition belongs to the low temperature region (S160).

Specifically, in this step, it is determined whether or not the current indoor temperature is equal to or lower than the upper limit temperature of the first low temperature region.

The case where the current indoor temperature is lower than the highest temperature of the first low temperature Zone and thus the indoor temperature Zone (RT Zone) to which the current temperature belongs is Z7 or more means that the temperature difference between the cool air inside the refrigerator and the indoor air is relatively low due to the very low indoor temperature, and thus the loss of the cool air is not large. As a result, the period for driving the freezing chamber fan is relatively long, and the driving time is also controlled to be short.

The long driving period of the freezing chamber fan means that a time required to re-drive the freezing chamber fan again after stopping the operation of the freezing chamber fan is long. Therefore, since the compressor is operated at the maximum cooling capacity in a state where the freezing chamber fan is stopped, thereby circulating the refrigerant to cool the deep freezing chamber, there is a high possibility that the cold air inside the freezing-evaporating chamber in which the freezing chamber evaporator is accommodated flows into the bottom of the freezing chamber.

In this case, control is made to operate the freezing chamber fan in the first condition (S161).

In contrast, when it is determined that the indoor temperature Zone (RT Zone) to which the current indoor temperature belongs does not correspond to the first low temperature Zone, that is, it is determined whether or not it belongs to the second low temperature Zone having a higher temperature than the first low temperature Zone.

Specifically, if it is determined that the indoor temperature Zone (RZ Zone) to which the current indoor temperature belongs corresponds to the second low temperature Zone, the control is performed such that the freezing room fan is driven under the second condition (S171).

Here, in the above table, the second low temperature Zone may include an indoor temperature Zone (RT Zone)6, but is not limited thereto, and may further include an indoor temperature Zone (RT Zone)5 corresponding to a middle temperature Zone.

The first and second conditions for driving the freezing chamber fan are defined as a ratio of a driving time and a stopping time of the freezing chamber fan. The freezing chamber fan stop time in the first condition may be set to be longer than the freezing chamber fan stop time in the second condition.

For example, in the first condition, a ratio of a stop time (off time) of the freezing chamber fan to a driving time (on time) of the freezing chamber fan may be 3 or more. More specifically, under the first condition, the operation of keeping the stopped state for 225 seconds after the freezing chamber fan is driven for 75 seconds may be controlled to be repeatedly performed. Here, it is to be understood that the ratio of the stop time to the driving time of the freezing chamber fan is not limited to the above-disclosed condition.

In addition, in the second condition, a ratio of a stop time of the freezing chamber fan to a driving time of the freezing chamber fan may be 5 or more. More specifically, in the second condition, the operation of keeping the stopped state for 375 seconds after the freezing chamber fan is driven for 75 seconds may be controlled to be repeatedly performed.

Here, the lower the indoor temperature is, the longer the off time of the freezing chamber fan is designed for, for the following reasons.

In detail, although the cold air sinking phenomenon caused by the cold air reverse-permeated from the freezing evaporation chamber to the freezing chamber is more serious as the indoor temperature is lower, if the on/off ratio of the fan is set to be small in order to eliminate the phenomenon, the supercooling phenomenon of the freezing chamber may be caused.

In other words, if the off time of the freezing chamber fan is shortened because the cold air sinking phenomenon becomes severe, the supercooling phenomenon of the freezing chamber may be caused by the relatively frequent cold air circulation of the freezing chamber.

Therefore, it is preferable to set the off time of the freezing chamber fan to be longer as the indoor temperature is lower, in order to prevent the freezing chamber from being supercooled while eliminating the cold air sinking phenomenon.

In the first and second conditions, the freezing chamber fan may be controlled to be kept constant at a certain speed, and as an example, may be controlled to be driven at a low speed, but is not limited thereto.

In the first and second conditions, the cold air of the freezing chamber can be sunk to the bottom of the freezing chamber by periodically rotating the freezing chamber fan at a low speed (or other speed), thereby minimizing the phenomenon of temperature non-uniformity in the freezing chamber.

In addition, the control part determines whether the refrigerator power is turned off while the freezing chamber fan is repeatedly driven and stopped at a set speed under any one of the first and second conditions (S180), and returns to the step for determining whether the deep freezing chamber mode is in an on state if the power is maintained in the on state (S110).

Hereinafter, a method of controlling the output of the freezing chamber fan when the freezing chamber load coping operation is not generated in the state where the deep freezing chamber mode is off will be described.

In detail, when the deep freezing chamber mode is in the closed state and it is determined that the second freezing chamber load coping operation input condition is not satisfied, at least one or more steps of the following steps may be executed: a step (S190) for judging whether the freezing chamber is in a non-operation state; a step (S191) for judging whether the freezing chamber door is opened; for judging freezingWhether or not the elapsed time after the start of the room operation has elapsed the set time t₁Step (S192); and for judging whether the elapsed time after the door of the freezing chamber is closed has elapsed the set time t₂Step (S192).

Controlling to stop driving the freezing compartment fan (S200) if at least one or all of the following conditions are satisfied: the freezing chamber is in a non-running state; the door of the freezing chamber is opened; the elapsed time after the start of the operation of the freezing chamber does not reach the set time t₁The case (1); or the time elapsed after the freezing chamber door is closed does not reach the set time t₂The case (1). It can be said that this is substantially the same as the process of performing steps S120 to S123 of fig. 10.

As described in fig. 10, the execution sequence of the steps S190 to S193 is not limited to the sequence disclosed in the flowchart.

In contrast, if all the conditions of the steps S190 to S193 are not satisfied, a process of detecting the indoor temperature and determining which temperature region the detected indoor temperature is in is performed (S194). Here, it is not excluded that the steps S190 to S194 are all omitted and the process goes directly to the step for detecting the indoor temperature (S194).

On the other hand, if it is determined that the detected indoor temperature belongs to the high temperature range, the control may be such that the freezing compartment fan is driven at the first speed. If it is determined that the detected indoor temperature does not belong to the high temperature region, the control is performed such that the freezing chamber fan is driven at the second speed.

It is determined whether or not the temperature of the freezing room has entered the satisfied temperature range a shown in fig. 7 (b) (S197), and if it is determined that the temperature of the freezing room has not entered the satisfied temperature range, the routine returns to the step of determining whether or not the freezing room is not in operation (S190).

Here, it should be clear that if it is determined that the freezer compartment temperature does not enter the satisfactory temperature region a, the control may be returned to any one of steps S191, S192, S193, and S194. Alternatively, if the freezer compartment temperature does not reach the satisfaction temperature (S199), control may be returned to the step for determining whether the deep freezer compartment mode is in the on state (S110).

On the contrary, if it is judged that the temperature of the freezing chamber is within the temperature satisfying range, the control is performed such that the fan of the freezing chamber is operated for a set time t₃Is driven at the third speed (S198, S199). If the set time t passes₃Then, the driving of the freezing chamber fan is stopped (S200), and the process returns to the step for determining whether the deep freezing chamber mode is in the on state (S110).

It can be said that the control method of steps S194 to S200 in fig. 11 is substantially the same as the control method of steps S124 to S130 in fig. 10. However, unlike the case where the deep freezing chamber mode is in the on state, if the deep freezing chamber mode is not in the on state, the process goes to the step (S110) of determining whether the deep freezing chamber mode is in the on state after the freezing chamber fan is stopped.

That is, the difference is that, when the deep freezing chamber mode is in the on state, the operation proceeds to a step (S140 or less) for determining whether or not to perform the cold air sinking operation.

The first to third speeds may be regarded as the same as the first to third speeds illustrated in fig. 10.

Claims

1. A control method of a refrigerator, wherein the refrigerator comprises:

a refrigerating chamber;

a freezing chamber separated from the refrigerating chamber;

a deep freezing chamber accommodated inside the freezing chamber and partitioned from the freezing chamber;

a thermoelectric module configured to cool the temperature of the deep freezing chamber to a temperature lower than the temperature of the freezing chamber;

a deep freezing chamber temperature sensor for detecting the temperature inside the deep freezing chamber;

a freezing chamber temperature sensor for detecting a temperature of an inside of the freezing chamber;

a freezing chamber fan which forces air inside the freezing chamber to flow; and

a control part for controlling the driving of the freezing chamber fan,

if the heat load penetrates into the freezing chamber, the freezing chamber load coping operation is executed,

the control method is characterized in that it comprises the steps of,

the load handling operation input conditions of the freezing chamber are set to be different depending on whether or not the deep freezing chamber mode is in an open state.

2. The control method of a refrigerator according to claim 1,

if the deep freezing chamber mode is in the opening state, the first freezing chamber load is applied to deal with the operation input condition,

if the deep freezing chamber mode is in the closed state, the second freezing chamber load is applied to meet the operation input condition,

the minimum value of the thermal load satisfying the first freezing compartment load coping operation input condition is set to be lower than the minimum value of the thermal load satisfying the second freezing compartment load coping operation input condition.

3. The control method of a refrigerator according to claim 2,

if the load handling operation input condition of the freezing chamber is satisfied, judging whether the indoor temperature condition is satisfied,

the indoor temperature condition is differently applied according to the on/off state of the deep freezing chamber mode.

4. The control method of a refrigerator according to claim 3,

an indoor temperature range (RT Zone) in which the load of the freezing chamber can be handled when the deep freezing chamber mode is turned on is defined as a first indoor temperature range,

an indoor temperature range (RT Zone) in which the load of the freezing chamber can be handled when the deep freezing chamber mode is closed is defined as a second indoor temperature range,

the first indoor temperature region is set to be wider than the second indoor temperature region,

the lowest indoor temperature belonging to the first indoor temperature region is set to be lower than the lowest indoor temperature belonging to the second indoor temperature region.

5. The control method of a refrigerator according to claim 4,

if it is determined that the indoor temperature Zone (RT Zone) to which the current indoor temperature belongs is an indoor temperature Zone in which the load-coping operation of the freezing compartment can be put into operation, the control unit first determines whether or not the load-coping operation-putting-in condition of the refrigerating compartment is satisfied.

6. The control method of a refrigerator according to claim 5,

if it is determined that the refrigerating room load coping operation input condition is satisfied, the refrigerating room load coping operation is stopped and the refrigerating room load coping operation is executed first.

7. The control method of a refrigerator according to claim 6,

the freezing chamber fan is driven at a low speed while the refrigerating chamber load coping operation is performed.

8. The control method of a refrigerator according to claim 7,

when the temperature of the refrigerating chamber enters the temperature-satisfying range, the refrigerating chamber load handling operation is ended, the freezing chamber load handling operation is released, and the driving of the freezing chamber fan is stopped.

9. The control method of a refrigerator according to claim 8,

when the freezing chamber load coping operation is released while the deep freezing chamber mode is in the on state, the procedure returns to the step of judging whether the first freezing chamber load coping operation input condition is satisfied.

10. The control method of a refrigerator according to claim 8,

when the freezing chamber load coping operation is released while the deep freezing chamber mode is in the closed state, the procedure returns to the step of determining whether or not the second freezing chamber load coping operation input condition is satisfied.

11. The control method of a refrigerator according to claim 7,

if the deep freezing chamber mode is in the opening state and the temperature of the refrigerating chamber enters a temperature satisfying area, the load coping operation of the refrigerating chamber is finished,

while the freezing chamber fan is kept driven at a low speed, the control unit determines again whether or not the first freezing chamber load handling operation input condition is satisfied.

12. The control method of a refrigerator according to claim 7,

and if the deep freezing chamber mode is in an opening state and the temperature of the refrigerating chamber enters a temperature satisfying region, ending the load coping operation of the refrigerating chamber and continuously executing the load coping operation of the freezing chamber.

13. The control method of a refrigerator according to claim 5,

if it is judged that the refrigerating room load coping operation input condition is not satisfied, the refrigerating room load coping operation is executed,

the load handling operation for the freezing chamber is canceled when the temperature of the freezing chamber enters a temperature satisfying range or a set time has elapsed after the start of the load handling operation for the freezing chamber.

14. The control method of a refrigerator according to claim 13,

when the temperature of the refrigerating chamber enters the upper limit temperature range during the execution of the load handling operation of the freezing chamber, the mode is switched to a simultaneous operation mode for simultaneously cooling the refrigerating chamber and the freezing chamber.

15. The control method of a refrigerator according to claim 14,

when at least one of the refrigerating chamber temperature and the freezing chamber temperature enters a temperature satisfying region while the simultaneous operation mode is executed, the freezing chamber load handling operation is canceled.

16. A control method of a refrigerator, wherein the refrigerator comprises:

a refrigerating chamber;

a freezing chamber separated from the refrigerating chamber;

a freezing chamber evaporator for cooling the freezing chamber;

a freezing and evaporating chamber for accommodating the freezing chamber evaporator;

a freezing chamber fan configured to supply cold air of the freezing evaporation chamber to the freezing chamber;

a temperature sensor for detecting the temperature inside the deep freezing chamber;

a deep freezing chamber fan for forcing the air in the deep freezing chamber to flow;

a thermoelectric module configured to cool a temperature of the deep freezing chamber to a temperature lower than a temperature of the freezing chamber, the thermoelectric module comprising: a thermoelectric element having a heat absorbing surface facing the deep freezing chamber and a heat generating surface defined as a surface opposite to the heat absorbing surface; the cold side radiator is in contact with the heat absorbing surface and is placed on one side of the deep freezing chamber; a hot-side radiator in contact with the heating surface; and

a control part for controlling the refrigerator door load responding operation to be executed preferentially and the freezer door load responding operation to be interrupted if the freezer door load responding operation conflicts with the refrigerator door load responding operation,

the control method is characterized in that it comprises the steps of,

when the load-handling operation of the freezing chamber door and the load-handling operation of the refrigerating chamber door conflict with each other in the closed state of the deep freezing chamber mode, the freezing chamber fan is controlled to stop and the freezing chamber valve is closed to prevent the refrigerant from flowing to the freezing chamber evaporator,

when the freezing chamber door load operation conflicts with the refrigerating chamber door load operation in the open state of the deep freezing chamber mode, the control unit closes the freezing chamber valve to prevent the refrigerant from flowing to the freezing chamber evaporator and controls the freezing chamber fan to rotate at a first speed (v)_a) And driving the water vapor flowing into the freezing chamber to flow into the freezing chamber evaporator so as to reduce the frost formation degree on the outer wall of the deep freezing chamber.

17. The control method of a refrigerator according to claim 16,

when the load-handling operation input condition of the freezing chamber door is satisfied and the conflict does not occur with the load-handling operation of the refrigerating chamber door, the control unit adjusts the opening degree of the switching valve to flow the refrigerant to the freezing chamber evaporator and controls the freezing chamber fan to have a second speed (v)_b) Drive, wherein the second speed (v)_b) > said first speed (v)_a)。

18. The control method of a refrigerator according to claim 16,

if the freezer door load coping operation conflicts with a freezer cooling operation, controlling to preferentially execute the freezer door load coping operation and interrupt the freezer cooling operation,

in a case where the deep freezing chamber mode is in an on state, the freezing chamber temperature is within a satisfied temperature region divided with reference to a second grade temperature (N2), and the deep freezing chamber temperature is within an unsatisfied temperature region divided with reference to a third grade temperature (N3) lower than the second grade temperature (N2),

and controlling to perform an operation in which the freezing chamber fan is repeatedly driven and stopped at a predetermined cycle to reduce a temperature difference between an upper space and a lower space of the freezing chamber from becoming large.

19. The control method of the refrigerator according to claim 18,

the stop time of the freezing chamber fan is set to be longer than the driving time.

20. The control method of the refrigerator according to claim 18,

in order to reduce the temperature difference between the upper space and the lower space of the freezing chamber from becoming large, the freezing chamber fan is controlled to be at a third speed (v)_c) Drive, wherein the third speed (v)_c) < the second speed (v)_b)。